My name is Alexander FufaeV and here I write about:

# RMS Values of Voltage and Current. Why?

Using the RMS (»Root Mean Square«) values for sinusoidal voltage \( U_{\text{rms}} ~=~ \frac{U_0}{\sqrt{2}} \) and current \( I_{\text{rms}} ~=~ \frac{I_0}{\sqrt{2}} \), the formula for electric power can be written in the following form:

$$ \begin{align} P ~=~ U_{\text{rms}} \, I_{\text{rms}} \end{align} $$

The equation has the same form as the electric power for DC current and DC voltage:

$$ \begin{align} P ~=~ U_{0} \, I_{0} \end{align} $$